Oxygen therapy is the administration of oxygen as a therapeutic modality. It is widely used for a variety of purposes in both chronic and acute patient care as it is essential for cell metabolism, and in turn, tissue oxygenation is essential for all physiological functions. Oxygen therapy should be used to benefit the patient by increasing the supply of oxygen to the lungs and thereby increasing the availability of oxygen to the body tissues, especially when the patient is suffering from hypoxia and/or hypoxemia. Oxygen therapy may be used both in applications in hospital or in home care. The main home care application of oxygen therapy is for patients with severe chronic obstructive pulmonary disease (COPD).
Oxygen may be administered in a number of ways. A preferable way of oxygen administration is by using a so called on demand generation of oxygen. Referring to this, commercial solutions, so-called oxygen concentrators or separators, respectively, are widely known. These oxygen concentrators mostly separate oxygen from an oxygen comprising gas, so that the oxygen is provided on demand, i.e. directly before use. Most known oxygen concentrators require a compressor to compress the oxygen comprising gas. Furthermore, oxygen, preferably pure oxygen, has to be generated. Most known oxygen concentrators thus comprise an organic membrane to separate oxygen from the oxygen comprising gas.
The major drawbacks of the known oxygen concentrators are high costs and a limited convenience with respect to noise. Furthermore, undesired constituents of the oxygen comprising gas, mostly nitrogen, are adsorbed on the membrane thereby causing the requirement of a so-called swing process by which the adsorbed gas is desorbed from the membrane. During that desorption step, a separation of oxygen is not possible, because of which two membranes are desired which further increases the costs. Apart from that, the compressors are mostly noisy leading to a decreased convenience especially when the oxygen concentrator is used overnight. Furthermore, the generated oxygen is non-sterile, because of which a further measure of disinfection is often desired or necessary.
Known from U.S. Pat. No. 6,623,714 B2 is a method of separating oxygen from an oxygen comprising gas with the use of a ceramic membrane unit. According to this method, a feed stream is compressed and heated afterwards, and the heated and compressed stream of oxygen comprising gas is then guided through a heated ceramic membrane. Due to the properties of the ceramic membrane being located in the membrane unit, an oxygen permeate is formed composed of at least a portion of the oxygen contained within the compressed feed stream and consequently a retentate is formed containing at least a portion of the residual components of said compressed feed stream.
However, especially for therapeutic applications being directed to the treatment of COPD, it is discussed that a certain amount of nitric oxide enhances the therapeutic effect. Consequently, additionally to an arrangement for generating oxygen, an arrangement for generating nitric oxide may be provided. The nitric oxide or a gas comprising the latter may then be guided into the stream of oxygen, or oxygen comprising gas, respectively.